Bad old images below...

Spoiler - click to reveal

New ones:
XFG

The entire fleet.

Nice renders, but the odd scaling of the different cars ruins it a little bit for me...

It would be nice to see a render where all the cars have been placed in the same scene, so that they show in each others' reflections, but I'm assuming you've done it this way to cut down on rendering overheads and time?

If you're not averse to some advice, one possibility I could suggest is placing the cars in the same scene and framing the shot, and then hiding all but one of the cars for each render in turn, and then compositing them all back together once done. This would keep the scale and positioning constant and realistic. It wouldn't have the realistic reflections of the other cars though, but it would make the render times a little more manageable maybe.

Also, look into rendering Alpha channels when rendering the main image - most rendering software will do them at the same time, incorporated into the image as a 4th channel, or as a separate file. They take all of the headache out of clearcutting, and make semi-transparent parts such as windows much easier to deal with. It would also help to avoid that hard edge that shows where the floor ends in each rendered image when comping them together.

I'm totally open for advice. These are less supposed to be amazing shots, and more to just show off the team skins

I used the popular "how to render with blender" and made 4 individual renders, then just used GIMP and placed each image as a layer on top of the other (mainly just to put them all in one image).

I'm not that experienced with renders, and these tips will be helpful.